1. Field of the Invention
The present invention relates to a method of producing a one part organopolysiloxane composition having good long-term storage stability at room temperature.
2. Description of the Related Art
Curable organopolysiloxane compositions which contain an organohydrogenpolysiloxane having silicon-bonded hydrogen atoms (Si-H groups) and an organopolysiloxane having aliphatic unsaturated hydrocarbon groups (e.g., vinyl groups) bonded to silicon atoms and use an addition reaction (hydrosilylation) of the Si-H group to the vinyl group or the like are conventionally well known.
Organopolysiloxane compositions prepared by adding various retarding agents to such compositions so that the curing reaction at temperatures around room temperature is suppressed to improve the long-term storage stability and can be cured by heating the composition to facilitate the hydrosilylation when it is to be used are suggested.
For example, as retarding agents of this type, acetylene compounds are disclosed in U.S. Pat. No. 3,445,420 and hydroperoxide compounds are disclosed in U.S. Pat. No. 4,061,609.
However, where an acetylene compound is used as a retarding agent, since it is volatile, a problem arises in the storage stability of the composition in an open system, and the acetylene group may affect the crosslink density to affect adversely the physical properties of the cured product in some cases.
On the other hand, where a hydroperoxide compound is used as a retarding agent, such problems do not arise. However, it is found that there are problems that the viscosity increases immediately after the production of a composition and that curing delay occurs as the period of the storage of the composition becomes longer. If the amount of the retarding agent to be added is increased in order to prevent this viscosity increase phenomenon, the curing delay due to the aging becomes more conspicuous, and in some extreme cases, curing would not even take place at all.